Identifying poisonous plants accompanies finding edible plants in ancient foraging societies utilized to capture prey ‘toxic’ from Greek ‘toxikon’ = arrow poison Ebers Papyrus list plant toxins known to Egyptians agents of war capital punishment Renaissance age in Europe was full of renowned ’poisoner’s who rose to power Thousands of plants known to contain poisons many in our backyards!
Curare is arrow poison used by S. American tribes causes quick paralysis Over 70 species, from different tribes,used to make curare Blocks nerve impulses at the junction of nerve and muscle turbocurarine eventually isolated used in surgery because effects reversible
Many common landscape plants are poisonous or fatal! often to children Oleander has more then 50 toxic compounds planted in CA & southern states hot dogs roasted on sticks can be fatal Yews (Taxus spp.) can lead to respiratory or cardiac failure grown as hedges Rhododendron/Azaleas have poisonous leaves tea made from leaves, flowers, pollen can be deadly Delaware Indians used tea as suicide potion blocks nervous regulation of heart
Spruge family (Euphorbiaceae) contains poison milky sap Poinsettia, crown of thorns, pencil tree cactus Castor bean (Ricin communis) has deadly toxic seeds ingestion of 1 seed can kill a child Toxic protein ricin inhibits protein synthesis in the intestinal wall causes clumping of red blood cells symptoms are nasty symptoms do not develope for hours or days! most deadly natural poison known Poison cigarette in Breaking Bad
Numerous plants poisonous to sheep and cattle can be passed to humans (milk) White snakeroot impacted settlements west of Appalachian mtns all plant parts contain toxic alcohol tremetol cattle ingestion lead to ‘trembles’ human who drink milk had similar symptoms blocks breakdown of lactic acid in liver Milk vetches (locoweeds) toxic to horse, sheep, goats & cattle widespread in western US contain alkaloids that impact CNS lead to paralysis
Plants can puncture with spines, thorns, prickles, burrs or hairs In cacti, spins are modified leaves! wards off animal predation can be barbed or not barbed Some plants have ‘stinging hairs’ that also inject chemical irritants Stinging nettle family hollow hairs like syringe strangely also edible
Review: plants produce many secondary compounds many reduce palatability for insects Pest chemical defenses: bitter, toxic or alter life cycle these ‘poisons’ can be harnessed by humans Pyrethrum = made from Chrysanthemum flower nerve poison for household insects common in flea medications may bioaccumulate in streams Rotenone = roots from tropical legumes nervous system paralysis in fish used by indigenous peoples to catch fish common garden insecticide
Certain plants or plant parts are capable of causing allergic conditions to sensitive individuals Reactions considered hypersensitive reactions immune systems differentiates ‘non-self’ produce immune response Multiple pathways for allergies respiratory from pollen skins reactions to oils/resins food allergies
~20% of humans suffer significant allergies hay fever and asthma most common Hay fever: respiratory reactions to pollen mild symptoms but long lasting 17 million visits to physician each year Plants causing hay fever are wind-pollinated abundant amounts of small pollen Glycoproteins, allergenic pollen proteins proteins trigger growth of pollen tube trigger immune response in humans
Ragweed, Ambrosia spp, most notorious hay fever plant annual or perennial herbs name means “food of the gods” 1,000’s of small flowers release 1 billion pollen grains release August - September may be longer in southern states 1 million tons of pollen each year Invasive and spreading in Europe introduced on grain shipments after WW1
Increasing temperatures alter growing seasons for plants spring-flowering plants most sensitive May trigger earlier starts to pollen season may also increase pollen amounts Elevated CO2 experiments show increase growth of ragweed higher pollen production study found increase in allergenic proteins later frost dates increase ragweed season
Allergic reaction of skin to something touched delayed hypersensitivity Poison ivy, Toxicodendron readicans, cashew family widespread in US & Canada leaves alternate w/ 3 leaflets leaf margins show several forms 1 of every 2 people allergic Poison oak & sumac less widespread Urushiol, a resin, is allergen slight bruising of leafs releases resin binds to skin proteins rapidly
~4% of US population suffers from food allergies greatest in children under 3 100’s of foods cause reactions Symptoms are wide-ranging diagnosis difficult Peanut most important allergen as most commonly involved in anaphylaxis food packages indicate common allergens Can GMO’s have hidden allergens? soybean w/ gene from Brazil nut StarLink corn
Latex is a milky exudate produced by many plants hydrocarbons, alkaloids, resins, terpenes Natural source of rubber, Hevea brasiliensis hydrocarbons w/ elastic properites Natural rubber latex found in gloves, tubing & medical supplies 70% of rubber synthetic but natural superior ~4% of population allergic to latex symptoms from hives to inflammation companies focus on low-allergen latex